of ketboit



Jan. 3, I928. 1,655,181

J. E. CLARK SAFETY CIRCUIT FOR TRAIN CONTROL SYSTEMS Filed Feb. 1. 1926lNVENTbR KT ORNEY Patented Jan. 3,

,- umrsn STATES 1,655,181 PATENT ounce.

ones-n, or nnrnorr, nienrean, assrenon ro CONTINUOUS TRAIN conrnor.oonronn'rron, or DETROIT, mrcnrean, a oonronarron" or MICHIGAN.

SAFETY GlRCTJ'IT FOB TRAIN-CONTROL SYSTEMS.

application filed February (this invention relates to train controlsysterns whereby electro-magnetic waves are proymgated in the rails ofeach block into which the track is divided and include means whereby thewave lengths are determined by the occupancy oi thetrack ahead, whichsysten'is further comprise l.oopcollector coil circuits on the.locomotive for picking up such electro-magnctic waves and utilizing themfor the p :poseoi permitting or obstructing the flow of current throughelectron tubes on the locoi'notives and of relays controlled bysuchcurrents to govern the operation oi? clectro-pneulnatic valves connectedto the air brake systems oi. the locomotii This invention, consists in anovel circuit between a current source and the filaments oi. theelectron tubes to carry the current whereby the tubes are renderedactive, so connected to the collector. coils that all the coilsconstitute a portion of thiscircuit, no matter how manycoils areemployed, so that, should any one of the coils become broken tor anyreason whatever, the electron tubes immediately become inoperative andthe in- .-.1 :innentalities controlled thereby become inacnve, resultingthe air-brakes"operating to stop the train.

it further consists of the details of construction illustrated in theaccompanying drawing and particularly pointed out in the claims.

ln the accompanying drawing, Fig. 1 is 2. diagrammatic view of thepresent invention constituting a part of, an automatic train controlinstallation. 2 a iront elevation. of a coil-supporting bracket.

Similar reference characters refer to like parts throughout both views.i

the airbralte mechanism shown by the drawin is embodying the presentinvein tioh 1 designed to be used in connection with instruinentahtieson the locomotive which are controlled by electromagnetic waves flowingin the track rails overwhich the locomotive is passing, and attention iscalled to the Thomas E. Clark Patent Number 1,202,637, dated April 16,1918,,wh1ch shows 'nropagating mechanism for electromagnetic it yesattached to the exit ends oi the blocks into which the track is dirided.llach installation controlled by the next installation ahead andfunctions to prop; :2 rent shone wave length, say

in the plate circuits.

1, 1926. Serial No. 85,156.

8000 meters, when the conditions of the block of track 'iertaining tosuch installation are tor safety or clear, and current of another wavelength, say 6000 meters, when the conditions of such block are fordanger. Any otherdesired means may be eniploycd to propagate suchcurrents under clear and danger conditions.

The track installations adapted to the present train control devices areof such power and wave lengths that only a limited length t track at theexit end of each block is energized by these installations sullicientlyto all'ect the instrumentalities on the l0comotive. 'ieclied whilepassing over the remainders of the blocks.

The locomotive instrumentalities embody two collector coils 100 and101., one for each wave length, mounted on the locomotive where they canbe influenced by the lines of force of such electromagnetic waves. Theseconnect to two electron tubes 102 and 1023 which have the usualcharacteristic that when negative potential accumulates in the grids,the flow of electrons from the fila" ments to the platesis interruptedand therefore substantially stops the flow of current These platecircuits embody relays normally energized by the flow oi the current inthe plate circuits.

I prefer to use a two-voltage generator which may be driven in anydesired manner, The common wire to this generator for both voltages isthe heavy wire 105. l Vhen the coil 101 cuts lines of force of a currentin the rails or say 6000 meters wave length, current flows from thiscoil over wire 106 to the grid of tube 103, the grid lealt 10? connec-ngthis wire with the re turn wire 100, the usual condenser 108 be ingconnected into this circuit, which may be tuned to the desired wavelength by l adjustable condenser 110. The heating e11 cuit for thefilament of this tube is from the generator 104: over the wire 112. re.sistance 113. which reduces the voltage from say to .12 volts, wires114, 115 and i110, filament of tube 102, wires 117, 109 and 110,filament oi? tube 103, wire 119, adjustable resistance 120 to commonwire 105.

The reason for passing this current over the wires 115, 116, 109and 118is to cut out the current to both filaments should either ol the coils1.00 and 1.01 or the supports ill) fit

therefor be torn from the Wires US -11S through accident. But otherwise,current flows to these filaments at all tunes that the gene 'ator inoperation.

Each of these coils 100 and 101 is preterably mounted Within a shellsupported by a. trunking or hollow b 'ackct S1 extending down from abolster 82 forming partot the locomotive or other vehicle on which thisinstallation is nounted. The wires connected to these coils extend upthrough the brackets 81 and will he ruptured when the brackets arebroken or torn itrorn the bolster.

The receiver circuit 01 the coil comprises the Wires 1253 and 123,adjustable coudenser 12 1 and wires 125, 11-1- and 115. The gridcondenser 126 and grid leah 121' serve to impose negative potential on.the grid of tube 102. l' 'hen the grid of tube 103 hassutlicientnegative potential to obstruct the flow in the plate circuit,in-sutlicit-znt current flows to the relay 128 over the common Wire 105,adjustable resistance 1520, Wire 1'19, filament to plate in tube 103,and Wire 132 to this relay, from vvllicu current would normally flowover wire 131. armature 128 and Wire 129 to the high voltage side of thegenerator.-

But' it this circuit is interrupted (as shown) because or lack ofsuthcient current to energize this relay, its armature a con1- pletesthe following circuits for the red lamp R. From the common Wire 105,Wire 131, arn'iature 128. vvire 138, relay 13-1: and Wires 135 and 1141-to the generator. This now energized relay -3 1- attracts its armaturesand the circuit 110111 common \vire 105, armature 131", Wire 136,1amp Rand Wires 138 and 112 is established, a resistance 12:30 being providedto protect the low voltage lamps.

Therefore, when the coil 101 picks up ciirrrent. the red lamp R burns inthe cab.

Should the coil. 100 pick up current, then the tube 102 would passinsutlicicnt plate current and the relay 11 1- vould be deenergized, anda circuit consisting of the common Wire 1055, wire 1 1:2. armature 110,Wire 143 green lan'ip G. and vires 1 13 and 112, would be completed. Thegreen lamp G therefore burns during only the interval thattheloconiiotive is passing over the. section of track in which the clearcurrent is "found. lhe red light, however, when it starts burning, {OOPSon burning until the coil 100 picks up clear current from an energizedsection at the exit end of some succeeding block, and this results 'llOll'l the circuit of its relay13t being closed through the armature lttl Wire 1 1st, armature 131: Wire 133, relay 134e, \VllCS 114; and1.12. Butwhen the relay 140 becomes de-energized by reason 01? the coil100 picking up current, this circuit to relay 'S-l-t pencil and the redlamp ceases to burn. No current will pass to this red lamp until thecoil 101 again picks up current.

1111 electro-pnenmat,ic "alvc is emplovcd to control the operation olthe air bral-zcs and consists of a body 0 havinc a series ofsuperimposed chambers. A, magnet 100 is mounted in the upper chamber andhas lead Wires 161 and 102, and this magnet. When energized, draws doivnthe armature 103 and the stem 10 1-, which carries the valve 105 whichnormallv closes the passage between the chamber 100 to which the pipe161' connects, and. the chamber 108 which has a relief passage 100. Thesecond valve 1'70, on this stein, normally opens the passage between thechamber 100 and the chamber 171 to vvhich the pipe 1'72 counects.

The pipe 172 connects to the main air reservoir and the air pressurewithin the chamber 1'11 together with the small spring 113 aresuliicicnt to hold the valve 170 onto its seat, unless the magnet. isenergized to hold down this valve and H c stem. The pipe 16? connects tothe br: kc control mechanism which is held in normal position. as willbe described later on. by the prwsuro of air 'lroin the main reservoir,through pipes 112 and 101". But when the magnet is de-energized, thevalve 170 closes the passage between these pipes and the control airescapes through the reliet pas-- sage 100.

So long as relay 128 is energized, curicnl flows to the magnet oil thevalve 0 over will:- mon \vire 105, wire 1.31, armature 128, \virc 145,torestalling key 110. and wire 10:4. a rd from the valve 0 over \vn'es101 and 1:1 io

the enerator. But when the coil 201 l;l"l\.

a V I i no current and the rela 128 is oc-cr 'lZttl.

n this Cll'Clll-L is opened and the conncx i'lil between pipes 107 and172 is closed, which will result in the setting ol the air brahcs.

'lhe len th ol' tract: which carric.-- sutiici nl elcctro-n'm mlicillijl to influence the iu-iru mentz-ilities or. t oumtivc in so limit dthat. a train lllUX inn at ordinary speed l)2l.-t-r' over it before thecircuit betucrn tvvo certain vcir 1 t3 and 1111 is opened as herein--aliter cxplainial. will be undcrstood that tube 102 has nothing to dobut to put out lamp ll and to cause current to Hon to lump G. Tube 10;}coz'it rols the operation ol tlnelectro-pncumatic 'alvc.

d'hen rclav 128 is rlccnc1',1i4cd by reason oi coil 101 picking upcurrent, the circuit o1 this relay cannot again be closed so long arthiscoil functions. But as soon as current in this (oil ceases. the grid 01'tube 1031 l()t;t i

v it? its cli'ective negative bias o'l' potential so that current maynow l'lovv irom the lilamcnl to the plate (it this tube. This ma hesccured by depress-in key 116 which tl(n-it the circuit from thefilament to the plate cl tube ill) ilfi

too

[ill

103, to relay.128,.over Wire 1 17, key 146, Wire 148, switch 36, andWires 1.4-9 and 129 to the hi gh volta e side of the generator 1.04:.

.The sti rlvrircu1t (already traced) tor the relay 128 is immediatelyclosed by arn'iature.

128" over wire 129, so that the key 14-6 may be released to close thecircuit to the electropneiunatic valve. But while the coil 101 isreceiving current, this stick circuit cannot be closed and the platecircuit cannot carry current and the electro-pneumatic *alve can-- notreceive current so that the brakes must be applied unless the locomotivehas carried this coil 101 beyond the charged zone.

While. the mechanism hereinafter d3 scribed torn'is nopart of thepresent invention, a description thereof is given so that the operationof train control systeniis. of this character may be fully understood.

. In the ordinary air brake system installed. on many of thelocontiotives in use in this country, two manually operated brakecontrol valves 1. and lend an air operated distributing valve 3 areemployed. The valve '1. connects to the pipe 2 which in turn connects totlieti'ain pipe l5 and its function is to release the air in "this pipe2, which results in the application of the train brah'" to admit air tothis pipe from the main pres sure tank which results in the release ofthe train brakes and to control the action of the distributing valve 3whose function to apply and release the locomotive brakes simultaneouslyand proportionatelyto the action brakes, independently of the trainbrakes,

and to release the pressure on this air pipe releases the locomotivebrakes independently of the rain brakes, which may be desirable whenaheavy train is on adown grade and the engineer TVlEShGS to save hislocomotive brakes While still using his train brakes.

The distinction between the valves 1 and l is primarily that when valve1 releases the sure on the train pipe, the train bralms applied, butwhen valve a vent this, a manually operated cock was pro vided to permitescape otany such pressure in the locon'rotive air pipetothe valve 1 andthe open air, and this cock was closedwhen two locomotives operatedtogether as a doidileheader, in which case the brakes o'l releases the im'e'surc on its 2111' pure, the locomotive one locomotive had to beunder the control of the engineer of the other. This leakage dur ingdoubledieading would be watched and released by the second engineer.

l v'heu the valve 1 was in brake-release or running position and thecock was open, this leakage escaped through that valve, but when thisvalve was in l z.'ake-a1 iplying or lap position, the escape wasprevented so that the locomotive brakes would be applied by the actionot the distributor valve 3.

lheereticaliy, such leakage should not occur,

but in actual practice it is suliioicnt to rcquire the cock abovementioned.

In the present system, I have substituted an air operated valve 7 forthe cock above mentioned for the reason that an application of thebrakes because of the operation of the automatic train control systemshown. in. the drawing may occur when the valve 1. is in runningposition, in. which event no application of the locomotive brakes wouldresult unless the icy-pass provided for this leakage is closed. The openstop cockwould' therefore prevent the application of the locomotivebrakes. The air operated valve 7, therefore, is open during normal.operation of the locomotive but closed during the opertion of theautomatic train control system.

As above explained, When the coil 1.01 picks up danger current, themagnet 1.60 becomes (lo-energized and the pipe 167 is connected to therelief vent 169. The spring; 13 will therefore press th valve12 againstits seat 14. As soon, however, as thema o' net 160 is re-energized, airunder pressure will flow from the pipe 1T2 past the valve 170 throughpipe 1.67 to the space above the piston 10 and open the passage betweenthe pipe (Send the automatic valve The brake-control mechanism shown incross section at the middle of the drawing Elli llul

embodies a'valve chamber 20 with. a slide valve 21 therein connected toa stem 22 which is slidable by a piston. 23- in the small eyh inder 24.Belovvtliis chamber 20 is asec ond cylinder 25 containing a piston 26con nected to a stem 27 carrying the valve 222-; which normally engagesa seahiQ forming part of the chamber 30. Below the chain her 30 anothercylinder 32 in which the piston33 is slidaliile, being normally held upby the spring 34 on the stem 35, and this The cap cause of the magnetbeing deenergized,

the valve lTOclosing the pi ige between the pipes 1 6'? and 172 and thesmall valve opening the passage from the pipe to? The wires 148 and 149connect to the llfi.

3 ill) s im to the vent 169. This movement of the valve 21 is caused byair flowing "from train pipe through passages and41 and acting on asecond piston 42 on the stem 22.

While the valve 21 was in its normal position against the shoulder atthe right end of chamber 20, air under train pipe pressure flowed fromthe chamber 20 through the port 43 in the valve 21, through the passage44 to the upper end of the cylinder 25, through the passage 45 and pipe47 to the lower chamber of the valve body 49. From this chamber, airflows through pipe 50 to the tank 51.

At the same time the small valve 53 was held otl' its seat in the smallchamber 54 at the end of the main valve chamber 20 by the valve 21, thestem of the valve 53 being loose in its support and permitting a slowflow of air from this chamber 20 to the control tank 55 through pipe 56and into the upper chamber 57 of the valve 49.

A, smallertlexible diaphragm 59 and a larger flexible diaphragm 60 aremounted in the valve body 49 and support the valve 62 which normallyopens the vent to the pipe 63 which connects to a passage 64 openinginto the space 67 below the valve 21.

When the valve 21 has reached the position shown, the spring 66 forcesthe small valve 53 onto its seat, preventing leakage from the tank 55which retains normal train pipe pressure. The valve 21 by means of itsport 67 connects the passage 64 and pipe 63 to the whistle 68, and airflows from above the piston 26 and from the tank 51 through the pipe 63to this whistle. The reduction of air pressure above the piston 26 isrendered slow by this tank 51. hen the downward air pressure on thepiston 26 and stem 27 falls to less than the upward air pressurethereon, the piston and valve will rise and air from the train pipe willrush down intov the chamber 32, depressing the piston 3-3 and escapingthrough the holes 79. At the same time the contacts 36 and 87 separate,opening the fo'l'estalling-lrey circuit.

So long, therefore, as the pressure above the piston 26 is at not lessthan a certain percentage of the train pipe pressure, the circuitbetween the forestalling key and the valve 9 may be closed and theengineer may prevent the application of the brakes thereby, the circuitto the cleetro-pneumatic valve 9 being established as above described.

But it the engineer delays depressing his torestalling key until the airpressure above the piston 26 is sutlic'iently reduced to permit the airpressure below it to raise it and the valve 28, the rush of air downwardopens the switch between the wires 148 and 149 and holds this switchopen until the air pressure on the train line is su'liieiently reducedto cause an application of the air brakes, and

thereafter until the pressure :bove the pieton 233 falls so low that itcannot prevent the spring 34 from pushing up the piston 31). Should theengineer teed air into the train pipe in an endeavor to release thebrakes, such added air would assist in holding the valve 26 open, but ithe assists in reducing this train pipe pressure, the valve 28 will closeearlier.

The uppu: diaphragm 59 ot the valve 49 is always under initial trainpipe air pressure. when the pressure above the piston 26 and below thediaphragm 60 has fallen so that the total pressure below the diaphragm69 is less than the total pressure above the diaphragm 59, the valve 62closes and prevents further reduction, which results in the piston :26forcing the valve 2 3 to its seat, provided, oi course, the valve 1 isat hip position. The piston 33 is then lifted by its spring and thecontacts and engage to close the torestalling-key circuit, so that theengineer can reset the relay 128 as before described.

The details 01"- construction oi, this safety mechanism and theproportions of its parts may all he changed by those skilled in the artwithout departing from the spirit of my invention as set forth in thefollowing claims.

I claim 1. In a system of the class described, comprising collectorcoils mounted on a track vehicle, adjacent the track, a current source.two electron tubes, an electric circuit be tween each coil and the gridof one (it said tubes, and an electric circuit between the currentsourceand the filaments of both oil said tubes connecting to both 01said coils.

2. In a system of the class described, an electron tube, a currentsource to energize the tube, a coil adapted to be euergizcd bv currentfrom a stationary conductor, and circuits carrying the energzing currentfor the tube from the current source by way of the coil to the grid ol'the tube and a controlling current i'rom the coil to the tube.

3. In a system of the class described, an electron tube, a currentsource to energize the tube, a coil adapted to he euersrized hv currentfrom a stationary conductor, circuits carrying the energizing currentfrom the cu .cnl' source by way oi the coil in the tub and a controllingcurrent from the will to thegrid ot the tube, and a using enclosingsaid. coil and the adjacent portion of said circuit.

4. In a system of the class described, an electron tube comprising afilament. plate and grid, a current source to supply filament and platecurrent, and circuitsembodying a collector coil adapted to be energizedby current from a. stationary conductor, said circuits carrying cu rentfrom the currenl source through the collector coil to the lilaill] mentand plate, and a control current from the coil to the grid.

5. In a system of theclsss described, a. plurality of electron tubeseach comprising a filament, plate and grid; at current source tosupplyfilament and plate current to said tubes; an electric circuit tocarry current from the current source to the filaments and plates ofsaid tubes comprising a plurality of collector coils adapted to beenergized by currents from a stationary conductor; and independentconductors between said coils and said grids.

6. In a system of the class described, a current source a normallyenergized electire-pneumatic valve to control a brake systom, anelectron tube, a source of current of til coni mrutively loW tension anda source of current of higher tension, a circuit for the low tensioncurrent connecting to said valve, e relay to open and close saidcircuit, a circuit for the higher tension current including Rillh relayand the plate circuit of said tube,

7 adapted to be closed by said key to close the plate circuit to saidrelay to cause it to he rc'energized.

JAMES n outrun

